Researchers have demonstrated how to create a super-strong aluminum alloy that rivals the strength of stainless steel, an advance with potential industrial applications.

“Most lightweight aluminum alloys are soft and have inherently low mechanical strength, which hinders more widespread industrial application,” said Xinghang Zhang, a professor in Purdue University’s School of Materials Engineering. “However, high-strength, lightweight aluminum alloys with strength comparable to stainless steels would revolutionize the automobile and aerospace industries.”

New research shows how to alter the microstructure of aluminum to impart greater strength and ductility. Findings were detailed in two new research papers. The work was led by a team of researchers that included Purdue postdoctoral research associate Sichuang Xue and doctoral student Qiang Li.

The new high-strength aluminum is made possible by introducing “stacking faults,” or distortions in the crystal structure. While these are easy to produce in metals such as copper and silver, they are difficult to introduce in aluminum because of its high “stacking fault energy.”

A metal’s crystal lattice is made up of a repeating sequence of atomic layers. If one layer is missing, there is said to be a stacking fault. Meanwhile, so-called “twin boundaries” consisting of two layers of stacking faults can form. One type of stacking fault, called a 9R phase, is particularly promising, Zhang said.